1. Field of the Invention
Example embodiments in general related to an apparatus for performing an operation on a material, and also to a method of performing an operation on a material.
2. Description of Related Art
It is known to use belt filter presses for separating liquids from solid suspensions. Such filters can be employed in the treatment of sewage for dewatering purposes. Typically, a belt filter comprises two tensioned endless belts circulating around guide rollers with a pressure zone defined between the two belts. In addition to the pressure zone, the belt filter has a gravity zone where water can be drained from the matter undergoing treatment and a wedge zone where solids are prepared for presentation to the pressure zone at which the solids are subjected to pressure to extract water therefrom. At least one of the belts is formed of a water-pervious material to facilitate removal of the extracted water.
Present flat belt presses for dewatering sludge experience run off of the sludge and generally can only have 10 to 20 mm spread evenly across the belt. In an endeavour to prevent run-off, some flat belt filter presses have boards along the sides of the belt to contain the sludge. Even so, in operation, the spread of the sludge is not uniform across the belt and the entire belt is generally not used. Also there is a degree of spatter associated with the spreading of the sludge onto the belt and thus the process can be somewhat messy.
A particular problem with such belt filter presses is the difficulty in ensuring that the belts track correctly around the guide rollers, particularly at the region of the pressure zone where the belts co-operate to press the material undergoing treatment.
A recent development in relation to belt filter presses is disclosed in WO 99/07457 (Day) and is known as “V” filter. This development is an advance on the basic two-belt press in that it provides better spread of the sludge and more even distribution. Additionally, it removes the tracking problem of having more than one belt. However, it is limited in its applications to small capacity as it sags between the holding/compaction rollers which can result in stretching of the belts if over loaded. Further, it does not allow for a high hydrostatic pressure head as the liquid can only be filled to the top of the “V” bolt.